Apparatus for measuring the twist of shafts.



H. H. CUMMINGS.

APPARATUS FOR MEASURING THE TWIST 0F SHAFTS.

APPLICATION FILED NOV. 22. I911. Patented May 22,1917.

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H. H. CUMMINGS.

APPARATUS FOR MEASURING THE TWIST 0F SHAFTS.

APPLICATION FILED NOV- 22, 191].

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APPARATUS FOR MEASURING THE TWIST 0F SHAFTS.

APPLICATION FILED NOV- ZZ. 191].

1,227,043. Patented May 22,1917.

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H. H. CUMMINGS.

APPARATUS FOR MEASURING THE TWIST F SHAFTS.

APPLICATION FILED NOV. 22, 1911.

1,227,043. Patented May 22, 1917.

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flog/3 I j 26 Zbbzwaees: 32 [7121621531074 Q A ,fizmyfl 62017677267155UNITED STATES PATENT OFFICE.

HENRY H. CUMMINGS, OF NEWTON HIGHLANDS, MASSACHUSETTS, ASSIGNOR OF ONE-HALF TO ROWLAND R. GARY, OF ALEXANDRIA, VIRGINIA.

rrARA'rUs non MEASURING THE 'rwrsr or sHAFrs.

Specification of Letters Patent.

Application filed. November 22, 1911. Serial No. 661,796.

To all whom it may concern,

Be it known that I, HENRY CUMMINGS, citizen of the United States, andresident of Newton Highlands, county of Middlesex', and State ofMassachusetts, have invented an Improvement in Apparatus for Measuringthe Twist of Shafts, of which the following description, in connectionwith the accompanying drawings, is a specification,

elastic quality of the high grade steel "em-,-

ployed in the transmission shafting, wherein the elastic twistingdistortion of an integral section of such shafting is alwayssubstantiallythe same, (within the elastic limits of the metal) for agiven amount of power transmission, an accurate torsion meter can beassociated with and operated from anin-' tegral shafting section withoutinterfering with the normal operation thereof for transmission of powerand without requiring any of the complicated and cumbersome deviceshitherto involved in measuringpower transmission. My improvedmeterconsists in a device having operative attachment ,at separated points tothe transmission shafting, with connections arranged for cooperativeaction to indicate with precision and exactness the amount of elastictwist distortion present at any given time in the portionof the shaftingbetween such points. More specifically, in one preferred embodiment, theinvention consists in a device adapted to be housed'nearly in itsentirety in thehollow center of the transmission shafting com monlyused, with only the immediate recording elements extending withouttheshafting, thus disposing of the device so as to be entirely out ofthe way and efi'ectually protecting its parts from injury.

The invention will be better understood from the following detaileddescription, taken in connection with the accompanying I have discoveredthat drawings, and will be thereafter pointedout in the appended claim.

Referring to the drawings, v

Figure 1 is a side elevation partly in sec. tion and broken'away, of asection of power transmission shafting with my improved torsion meterfitted thereto.

Fig. 2 is a broken away elevation, showing a part of a powertransmission shafting line with one shaft section thereof fitted with myimprovements.

i Fig. 3 is a side or edge view, and Fig. l

is an end elevation partly broken away, of

Patented May 22, 1917.

the flanged end of a shaft section equipped with my improvements.

Fig. 5 -IS a detail sectional view of the transmission connection to therecording device.

Fig. 6 is a plan." Fig. 7 is a central vertical section of a holder forthe record sheet.

Fig. 8 is a view partly in section. and partly in elevation, and with aportion broken away, of a modification. Fig. 9 is a fragmentary detailof such modification taken on line 99 of Fig. 12. Figs. 10 and 11 aretransverse sections on lines 1010 and 11 -11 respectively of Fig..'

8; and

Fig. 12 is an enlarged fragmentary detail partly in section through therecording elements of such modified form;

While not limited thereto in. its broader aspects, my improved torsionmeter and recording device isshown by Figs. 1 to 4 in a preferredembodiment as applied to an integralsection 1 of the hollow shaftingcom:

.monly employed for the transmission of powerfrom the'turbine or othermotor to the propeller or' other part to be driven.

*These integral shaft sections are usually of considerable length,commonly about twenty feet, and I preferably'attach the cooperativeconnections of my improved device as near to theends of the sections aspossible, in order to take advantage of as long a range of elasticdistortion as can be haol. Within the hollow center of the selectedshaft section a shaft 2 is mounted, preferably tubular for the sake oflightness. This shaft is mounted at one end in a bearing spider 3,having a series, shown as four, ofspaced apart arms 4 extending radiallyto engage the inner wall periphery of shaft section 1 at one endthereof. Thisspider support is adapted to be immovably held at oradjacent one end of shaft section 1 by having the arms 4 provided withtransverse cuts 5 extending well across the same, so that the outer endsthereof may be forced out by expansion bolts 6 to grip the walls of theshaft section. As shown, the shaft 2 has a reduced end 7 fitted in ballbearings 8 carried by the spider'support 3, and extends thencesubstantially the entire length of shaft section 1 to an anchorsupport9. This support has a split collar 10 adapted to be rigidly clamped tothe shaft 2 by clamp bolts 11 and is provided with a series, shown asthree, of spaced apart guide bearings 12 for radially slidable anchorpins 13, having their outer ends pointed, as seen at 1 1- to bite intothe shaft section 1. The inner ends of these pins have screw threads 15formed thereon adapted to be engaged by cooperating threads on a conicalexpanding screw bolt 16, this screw bolt having its outer end 17 squaredor otherwise formed to receive an operating tool. Thus, with the collar10 rigidly clamped to the shaft 2 and with the anchor pins 13 forcedoutward to bite into the walls of shaft section 1, it is apparent thatthis end of the shaft 2 is held fixed relative to the shaft sec tion 1,so as to turn in unison therewith. The other end of shaft 2 adjacent itsreduced bearing portion 7 has clamped thereon a bracket 18, having asplit collar 19 clamped to the shaft 2 by screw bolts 20.

The bracket 18 has opposite projections 21 extending outward beyond thebearing spider 3 and passing between the arms l with sufficient playbetween said arms for limited angular movement. These projections havefixed thereto an arm 22 extending radially of the shaft and out to theperiphery of the end flange 23 of shaft section 1. As seen in Figs. 2and 4, this arm is housed within flange 23, this flange for this purposehaving a radial slot 24 in its end, somewhat wider than the arm 22 so asto permit the small angular movement of said arm i11- volved intheoperation of the recording device. The fiange 23 has fixed at itsinner side,- near its periphery, a bracket support 25 for the recordingmembers, and in this bracket a rock-shaft 26 is mounted on cone bearingscrews 27 shown as adjustably clamped in split portions 28 of thebracket. This shaft has fixed thereto a holder 29 in which a bar or rod30 is centrally fixed with oppositely extending portions which carry attheir ends the recording stylus or other marker points 31. As seen inFigs. 3 and 5, the bar 30 is bent around at either side so that themarker points 31 carried at its ends are in alinement with the center ofshaft 26 about which it turns. The holder 26 is connected with radialarm 22 for operation thereby. For this purpose the arm 22 has a bar 32rigidly connected therewith by an interlocking connection 33 heldclamped by a screw bolt 34, and this bar extends over the edge of flangefor connection with a projection 35 from holder 29. The extremities ofbar 32 and projection 35 are forked and are connected by a universaljoint 36, so that transverse movements of the bar 32 from angularturning of arm 22 are transmitted to effect a turning of holder 29 onits axis, and hence a corresponding swinging of the stylus carrying bar30. The pivotal connection 36 is comparatively close to the shaft axis26, and hence a small movement imparted thereto will cause aconsiderable displacement of the stylus points 31 since they are at arelatively great distance from the shaft axis. The fiange 22 has fixedthereto a shield or cover plate 37 which is bowed out to extend over thebar 30 and has arcuate slots 38 arranged to permit play of I the styluspoints 31 therein, these points projecting through the cover 37, as seenin Fig. 1.

The stylus points 31 thus carried by the flange 22 of a shaft sectionare adapted to make recording marks 011 a record sheet held in theirpath of movement on a suitable fixed support. For this purpose a recordsheet holder, designated generally 39 is mounted on a suitable fixedsupport 40.

The holder 39 comprises a base member 41 rigidly fixed to the support40, an intermediate bracket member 12 adjustable rel ative to the base11, and a record sheet carrier proper manually movable on the bracketi2. The bracket 4C2 has a depend ing under cut portion 4A circular incross section and fitted for limited sliding movement in a correspondingundercut way 45 in the base -11, and a follower block &6 slidif able inthe base ll and pressed by spring 4117 engages against the portion erand tends to move the bracket 4-2 forward, or to the right, in Fig. 7.This movement of the bracket is adjustably limited by a screw bolt 18threaded through an upstanding projection 49 of bracket 41-2 andextending through a slot in a projection 50 upstanding from the base 41.This screw bolt has an enlarged operating head 51, a shoulder 52 ofwhich is adapted to engage the projection 50, thus serving as a stop tolimit the forward movement of the bracket 42 the beaks 54 being adaptedto extend downward in position to engage corresponding laterallyprojecting portions of the base 41 at a point so that this engagementprevents the bracket 42 from moving too far forward. It is desirablethat provision be made for small angular adjustments of the recordsheet, so that the two stylus points will press evenly on the recordsheet in their different positions of recording movement, and theundercut portion l4: of the bracket 42 is made circular in crosssectionto permit this. To effect this angular adjustment, a turning plug56having an eccentric pin i 57 and a handle 58 projecting therefrom isjournaled in the bracket l2, the pin 57 working in a lengthwise slot59in the base 41 so that as the handle 58 is turned, the pin '57engaging the side of said slot causes an angular displacement of bracket42 relative to the base 4-1. The bracket 42 is slotted, as seen at 60,for *some'distance at either side of the bearing of plug 56, and a screwbolt 61 is passed transversely through this portion in position, whenset up,- to clamp the bearing walls of plug 56 against it, and tliusholdit fixedly in position.

The record sheet carrier proper 13 consists in a plate 62 fixed to a rodor bar 63 slidably mounted on the. bracket 12, the rod 63 having bearingin the upstanding projection 4&9 and adapted to be pressed forward bythe hand to bring the sheet carried thereby into engagement with thestylus points. The plate 62 is curved transversely, as seen in Fig. 6,in conformity with the angular sweep of the stylus points about axis 26and reduced extremities ea of this plate are guided in ways 65 formed ina casing 66, which extends around said plate and forward to its limit offorward adjustment, and shown with atop extension 66 to facilitateslipping of the record sheet down into position, and to protect theoperator from accidental injury;

In use, the parts are so adjusted that as the power transmitting shaftturns without elastic distortion from power trans mission, the twostyluspoints 31 move in nearly the same path over a record sheet held bythe sheet holder, making lines near together on the record. As soon,however, as twisting distortion of the shaft section 1 commences, therewill be a slight angular displacement between the flange 23 and theother end portion of shaft 1 to which the tubular shaft 2 is rigidlyfixed. This distortion results in a small turning of shaft 2 relative tothe flange 23, and thus the arm 22 with bar 32 carried thereby, is movedcorrespondingly relatively to the recorder axis shaft 26, whereby thebar 32through the pivotal connection 36 causes a turning of shaft 26,and thus a swinging of the vided' construction enabling styluscarryingrod 30, moving the stylus points, one farther to one side of the linesand the other farther to the other side of the other line previouslytraced. Thus the stylus or other marker points 31, in the rotation ofthe power transmission shaft,-

will now make marks wider apart than the marks before produced, and asthe extent of separation of these marks bears a definite and exactrelation to the power transmission which is causing the distortion ofthe It is to be observed that the measuring and recording device thusconstructed, is

adapted to be installed in connection with the ordinary power.transmission shaftmg line from the turbines, or other power source,

to the propellers or other parts to be driven, with its operativepartscompletely housed and taking up practically no additional space.Further, that the device is of ex tremely simple construction, having nocomplicated parts apt to get out of order and likewise'very light andcompact. The shaft 2, which is considerably the largest single elementof the device, can be made tubular as shown, with relatively thin walls,since it is only required to transmit the small impulse necessary towork the recording device; thus the .weight of the entire mechanism isan almost negligible quantity. A further important point is thatpractically no modification of the transmission shaft section 1 in whichthe device is installed is required, the illustrative embodiment shownonly requiring the shallow radial slot 2 1 in the face of flange 23, andvery small threaded holes in its periphery. r In Figs. 8 to 12 amodified form of the invention is shown, adaptedfor use with solidshafting. In this case a sleeve 2 is fitted over an integral shaftsection 1 extendingfor the greater part or the whole of the lengththereof and fixedly fastened to the shaft section at one end by anchorpins 13 threaded therethrough and having points to bite into the shaft,the other end of said sleeve having spaced apart bearing platesadjustable by others of the pins 13 so as to have a properly centeredand easy bearing fit on the shaft. The sleeve 2 may be of relativelythin light stock, since it is only required to transmit the smallimpulse for moving the recording devices, and, in practice, this. sleeveis preferably made in two halves clamped together by ears 67 with whichclamp bolts '68 engage, this dithe sleeve to be quickly and easilyfitted to the shafting.

The sleeve 2' extends to a point adjacent an end flange 23 of the shaftsection and this end has fixed thereto an arm 22 bent up alongsideflange 23. This flange has fixed thereto near its periphery a bracketsupport 25 having cone bearing screws supporting the rock-shaft 26,which, with the stylus carrying bar and stylus points, may be formedprecisely the same as in the first described form of the invention. Thearm 22 is connected with rock-shaft 26 by a bar 32 through a swiveljoint 36, this bar being similar in its form and function to bar 82,except that as it does not span the flange it is shorter. As shown, thearm 22 passes through a recess 69 in the bracket support 25, this beinglarge enough to permit the small angular movement of the arm required,the bracket support being fixed to the shaft flange by ears 70 extendingateither side thereof and clamped to the shaft flange as by screw bolts71. It will be understood that this form of the invention 0perates inprecisely the same manner as the first described form, the sleeve 2transmitting to the recording device the movement of the shaft sectionat one end thereof, While the other cooperative elements of therecording device fixed at the other end of the shaft section to theflange 23 cooperate with the arm connection 22 from the other end of thesleeve to record with precision the variations in twist distortion ofthe shaft portion between.

Other forms, modified more or less according to the requirements ofspecial kinds of transmission shafting may be devised without departingfrom the spirit of the invention, and I am also well aware that numerouschanges can be made in details of construction, for example, in thecharacter and arrangement of the transmitting connections between theseparated portions of shaft section 1, and in the cooperative relationbetween these for the purpose of effooting the recording movement of thestylus or other marker points. I therefore desire the particularembodiments of the invention shown to be understood as illustrative andnot restrictive. The present illustrative constructions are notnecessarily the preferred form of the invention, broadly considered, butare the preferred forms of this application.

Having described my invention, what I claim as new and desire to secureby Letters Patent is:

An apparatus of the kind described, comprising a hollow power shaftsection, a recording device mounted thereon adjacent one end thereof,and a connection for operating said recording device for the purposestated, including a member mounted within said shaft section remote fromsaid recording device with radially expansible anchor pins for bitinginto the shaft section, and a central expander for operating the same.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses.

HENRY H. CUMMINGS.

Witnesses:

C. L. Rooms, H. R. GARY.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. G.

